The present invention relates to an image forming system that is constituted by an image forming apparatus and a plurality of paper sheet processing apparatuses, which are coupled to each other in the system.
Various kinds of peripheral apparatuses are optionally coupled to the image forming apparatus, such as an electro-photographic image forming apparatus, so as to form a versatile image forming system.
This kind of image forming system is utilized not only as a utility in an office or a copy center, but also in the field of the POD (Print On Demand).
Conventionally, a single post processing apparatus, in which various kinds of processors, such as a stapler, a puncher, etc., are integrated, is generally combined with the image forming apparatus as the peripheral apparatus of the image forming apparatus employing the electro-photographic imaging method.
According as the functional demands for the peripheral apparatus have been diversified, however, it becomes difficult to integrate various kinds of functional structures into a single apparatus. As a result, a trend for forming and using the image forming system in which a plurality of peripheral apparatuses are concatenated with each other has emerged recently.
For instance, Patent Document 1 (Tokkai 2004-161466, Japanese Non-Examined Patent Publication) sets forth an image forming system in which a post processing apparatus having a folding function is coupled to the image forming apparatus, and further another post processing apparatus having an end stitching (plane stitching), a center folding and a saddle stitching functions is coupled.
Further, Patent Document 2 (Tokkai 2005-254362, Japanese Non-Examined Patent Publication) sets forth an image forming system in which an interface module is installed between the image forming apparatus and an post processing apparatus having a punching and a saddle stitching functions, so that the interface module can supply an additional paper sheet, other than the paper sheets conveyed from the image forming apparatus.
As described in Patent Documents 1 and 2 (Tokkai 2004-161466 and Tokkai 2005-254362 Japanese Non-Examined Patent Publication), in the configuration in which a plurality of post processing apparatuses are concatenated to the image forming apparatus, the conveyance path in the paper sheet processing apparatus to be disposed at an intermediate position (hereinafter, referred to as an relay conveyance apparatus) is designed to be as shorter as possible, in order to suppress the occurrence probability of the apparatus stopping accident due to the conveyance malfunction as a whole by reducing the conveyance malfunction in the relay conveyance apparatus, in order to improve the efficiency of the apparatus as a whole by increasing the processing velocity in the image forming mode in which the relay conveyance apparatus is deactivated, etc. In addition, even if the relay conveyance apparatus is designed to conduct a kind of paper sheet processing, a relatively simple processing structure is installed into the relay conveyance apparatus.
According to the reasons mentioned in the above, the relay conveyance apparatus tends to be designed in such a manner that the horizontal width of the relay conveyance apparatus is as shorter as possible when viewing it from the front of the image forming system.
In Patent Documents 1 and 2 (Tokkai 2004-161466 and Tokkai 2005-254362 Japanese Non-Examined Patent Publication), the post processing apparatus PZ and the interface module 4, both serving as the relay conveyance apparatus, are also designed in such a manner that the horizontal width of each of them is shorter than that of the image forming apparatus or the other post processing apparatus to be disposed at the both sides of them.